1. Field of the Invention
This invention relates to a battery-connecting plate for use with a battery holder which receives a large number of cylindrical batteries and which is mounted as in an electric vehicle, a method of producing same, and a wire protector.
2. Description of the Related Art
A battery-connecting plate 100 as shown in FIGS. 18A, 18B is conventionally used as a means of connecting a plurality of batteries in series or in parallel.
The connecting plate 100 includes a molded resin plate 103, a busbar 102 for connecting two batteries 101, fixed in the resin plate 103 by molding, the two batteries having nut-type positive and negative electrodes 101a, 101b, and a hexagonal and a square windows 103a, 103b in which electrode-connecting busbar holes 102a are exposed. The connection of the two batteries 101 is effected by fastening the busbar 102 to the nut-type positive and negative electrodes 101a, 101b with the bolts 104, at which time at the hexagonal window 103a a round terminal 105, which constitutes part of a voltage detecting circuit, is concurrently connected. In other words, the wire 106 connected to the round terminal 105 has a fuse 108 interposed in series therein and extends therefrom to a not-shown ECU. The fuse 108, which is enclosed in a fuse casing 107, is connected at its opposite ends, via a female terminal 109, to the wire 106.
FIG. 19 shows another example of a conventional connecting plate.
The connecting plate 100′ includes a molded resin plate 103 and a plurality of L-shaped busbars 102′ fixed in the resin plate 103 by molding, the L-shaped busbars having connection legs 102b′ of different lengths which have one end projected at one side of the molded resin plate 103. A wire 106 is welded at one end to the thus projected end of each L-shaped busbar and extends, via a fuse 108′ enclosed in a fuse casing 107′, to a not-shown ECU.
The fuse casing 107′ includes a base plate 110 and a pair of opposed L-shaped pressure-welding terminals 111 provided on the base plate, the pair of terminals 111 each having a base plate 111a whereat the wire 106 is welded and a pressure-welding piece 111b with a slot 111c rising from the base plate 111a, and the fuse 108 having its leads 108a′ pressure-welded via the slots 111c to the respective pressure-welding pieces 111b. 
The connecting plate 100 of FIG. 18 requires many connections in one circuit, for example, six connections in the voltage detecting circuit as shown at characters a, b . . . f, and also requires a large components count, possibly resulting in reliability in electric connection lowered. Further, the wired round terminals 105 require a manual operation one by one during their bolting, and hence as the number of wires 106 increases, it will become troublesome to bolt the round terminals 105 and to lay their wires 106.
On the other hand, the connecting plate 100′ of FIG. 19 requires L-shaped busbars 102′ of different sizes, and hence is disadvantageous in the production cost of the L-shaped busbars and their administration. Further, as is the case of the connecting plate 100, there are required a large components count and a large connections count in one circuit (five connections of a′, b′ . . . e′), and besides difficulty is encountered in protecting the welds between the wires 106 and their corresponding connection legs 102b′. 
Further, the connection wires 106 of the connecting plates 100, 100′, being directly connected to the related batteries 101, need to be properly protected. Due to the bulky member of the fuse casing 107, 107′ interposed, however, such a protection structure will inevitably become complicated.
FIG. 20 shows the case in which batteries are connected together not with a connecting plate, but directly with wires. In other words, each prism-shaped battery 101′ has positive and negative electrodes 101a′, 101b′, juxtaposed at one end, a main power wire 112 is used to connect neighboring batteries to each other, and wires 106 each with a fuse casing 107 (voltage detecting circuits), as in the case of FIG. 18, are connected to predetermined electrodes 101b′. 
Also in this case, a large components count is required. Further, the wires are dangerously exposed at many portions. In addition, due to the intersecting main power wires 112 and voltage detecting circuit constituting wires 106, the wiring becomes complicated so as to cause an improper wiring.
Under these conditions, it is conceived to embed the connection wires 106 of the connecting plate 100, 100′ in the molded resin plate 103 by insert molding.
With a conventional method of insert molding, however, as shown in FIGS. 21A, 21B, the wires 113, although firmly fixed inside the molded resin plate 114, become free outside the plate. Consequently, concentration of stress tends to take place at the roots 113a of the wires 113 located at the edge of the molded resin plate 114, so that in extreme cases the wires 113 are cut at the roots 113a by the action of a minimal external force. To prevent this, it is conceived to bundle the wires 113 with a band 115 or to fix the wires to a wall of the molded resin plate 114 through a fixture. The concentration of stress at the roots 113a, however, cannot be fully precluded, because the above operation is effected only after completion of the insert molding.
Further, there remains another cause of the cutting of the wires 113 at the roots 113a, which is the biting by the upper and lower dies 116 at the outlet of the wires.
Further, with a conventional method of insert molding, because, as shown in FIG. 22, the molten resin injected from the nozzle 119 of a molding machine into the mold 116 has a temperature higher than the heat-resisting temperature of the insulating cover 113b of commonly used wires 113, it has been required to use heat-resistant wires covered as with polyimide, resulting in a cost increase.